PLATE If. 



Stepbanocidaris bispinosa, /. 1. 



1. Seen from abactinal pole. 



Ftayllacanthus imperialis, /. 2. 



2. Seen in profile, nat. size. 



Phyllacanthus verticillata, /. 3. 



3. Seen from abactinal pole, two thirds nat. size. 



PhyllacEmthus baculosa, /. 4, 5. 



4. Seen in profile, two thirds nat. size. 



5. Seen from abactinal pole, two thirds nat. size. . 



Phyllacanthus dubia, /. 6, 7. 



6. Seen from below, two thirds nat. size. 



7. Seen in profile, two thii-ds nat. size. 



